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Ozone and nitric oxide induce cGMP‐dependent and ‐independent transcription of defence genes in tobacco
Author(s) -
Pasqualini Stefania,
Meier Stuart,
Gehring Chris,
Madeo Laura,
Fornaciari Marco,
Romano Bruno,
Ederli Luisa
Publication year - 2009
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2008.02711.x
Subject(s) - nicotiana tabacum , nitric oxide , biochemistry , alternative oxidase , biology , hypersensitive response , microbiology and biotechnology , second messenger system , chemistry , gene , signal transduction , plant disease resistance , endocrinology
Summary• Here, we analyse the temporal signatures of ozone (O 3 )‐induced hydrogen peroxide (H 2 O 2 ) and nitric oxide (NO) and the role of the second messenger guanosine 3′,5′‐cyclic monophosphate (cGMP) in transcriptional changes of genes diagnostic for biotic and abiotic stress responses. • Within 90 min O 3 induced H 2 O 2 and NO peaks and we demonstrate that NO donors cause rapid H 2 O 2 accumulation in tobacco ( Nicotiana tabacum ) leaf. Ozone also causes highly significant, late (> 2 h) and sustained cGMP increases, suggesting that the second messenger may not be required in all early (< 2 h) responses to O 3 , but is essential and sufficient for the induction of some O 3 ‐dependent pathways. • This hypothesis was tested resolving the time course of O 3 ‐induced transcript accumulation of alternative oxidase ( AOX1a ), glutathione peroxidase ( GPX ), aminocyclopropancarboxylic acid synthase ( ACS2 ) that is critical for the synthesis of ethylene, phenylalanine ammonia lyase ( PALa ) and the pathogenesis‐related protein PR1a . • The data show that early O 3 and NO caused transcriptional activation of the scavenger encoding proteins AOX1a , GPX and the induction of ethylene production through ACS2 are cGMP independent. By contrast, the early response of PALa and the late response of PR1a show critical dependence on cGMP.